title: Traffic-related air pollution and selected birth defects in the San Joaquin Valley of California.
abstract: BACKGROUND
  Birth defects are a leading cause of infant morbidity and mortality. Studies suggest associations between environmental contaminants and some structural anomalies, although evidence is limited and several anomalies have not been investigated previously.
  
  
  METHODS
  We used data from the California Center of the National Birth Defects Prevention Study and the Children's Health and Air Pollution Study to estimate the odds of 26 congenital birth defect phenotypes with respect to quartiles of seven ambient air pollutant and traffic exposures in California during the first 2 months of pregnancy, 1997 to 2006 (874 cases and 849 controls). We calculated odds ratios (adjusted for maternal race/ethnicity, education, and vitamin use; aOR) for 11 phenotypes that had at least 40 cases.
  
  
  RESULTS
  Few odds ratios had confidence intervals that did not include 1.0. Odds of esophageal atresia were increased for the highest versus lowest of traffic density (aOR = 2.8, 95% confidence interval [CI], 1.1-7.4) and PM10 exposure (aOR 4.9; 95% CI, 1.4-17.2). PM₁₀ was associated with a decreased risk of hydrocephaly (aOR= 0.3; 95% CI, 0.1-0.9) and CO with decreased risk of anotia/microtia (aOR = 0.4; 95% CI, 0.2-0.8) and transverse limb deficiency (aOR = 0.4; 95% CI, 0.2-0.9), again reflecting highest versus lowest quartile comparisons.
  
  
  CONCLUSIONS
  Most analyses showed no substantive association between air pollution and the selected birth defects with few exceptions of mixed results.
authors.affiliation: Stanford University, Stanford, California.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Padula
authors.forename: Ira B
authors.initials: IB
authors.lastname: Tager
authors.forename: Suzan L
authors.initials: SL
authors.lastname: Carmichael
authors.forename: S Katharine
authors.initials: SK
authors.lastname: Hammond
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Lurmann
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects*; D002140:California / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology / Q000209:etiology; D065817:Congenital Microtia; D004423:Ear / Q000002:abnormalities*; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000453:epidemiology / Q000209:etiology; D018811:Maternal Exposure / Q000009:adverse effects*; D011247:Pregnancy; D012189:Retrospective Studies
chemical_list: D000393:Air Pollutants
keywords: air pollution; birth outcomes; congenital anomalies; traffic